Spectacle frame with over-opening about a shifted bearing point

ABSTRACT

A spectacle frame includes sliding hinges which enable the arms to move from a stable open position, in which the end ( 306 ) of the arms is parallel to the end ( 313 ) of the endpiece ( 307 ), to an unstable wide-open position, by pivoting around a support point ( 311 ) belonging to a coincidence plane (P,P′) which passes between the knuckles (C 1 , C 2 ) of the hinges. The frame, which has a plane of symmetry (X,X′), is characterised in that the support point ( 311 ) is located closer to the plane of symmetry (X,X′) of the frame than the outer face ( 309 ) of the arms at the coincidence plane (P, P′).

The present invention relates to a spectacle frame comprising a hinge of“telescopic” type.

“Telescopic” hinges which, like most hinges, comprise two elements,bearing on one another and connected by a rotation pin, at least one ofthe two elements being movable, have the particular feature ofincluding, in the movable element, a tie-rod mounted so as to slide in ahousing and comprising a means for cooperating with the rotation pin,and a return spring.

When a spectacle frame is being fitted to a wearer's face, thesetelescopic hinges are advantageous because they allow over-opening ofthe sides, generally by 2 to 8°, which facilitates fitting, particularlyif this is done by another third party (the optician). The telescopichinges also improve the fit of the frame to the face since, because theover-opened position is unstable, once the sides are released by theperson fitting the frame they come to bear against the sides of thewearer's face, under the action of the return spring.

To ensure a comfortable fit for the wearer, it is important that thesides bear against the sides of the face with enough force to keep thespectacle frame in place but not so much as to be unbearable, theintensity of this bearing force depending on the return force.

Telescopic hinges are mass-produced and delivered in the assembled stateto lens manufacturers, so that the latter or the optician cannot adjusttheir return force.

In the over-opened position, the hinge-side end of the sides, known asthe proximal end, bears against a point on the hinge-side end, known asthe proximal end, of a stub forming part of the frame face, thuscreating a lever arm whose size is proportional to the thickness of thesides.

When the hinges are secured to thin sides, for example made of metal,this bearing point is located near to the rotation pin of the telescopichinges.

On the contrary, when the telescopic hinges are secured to thick sides,as sides made of acetate or injection-moulded thermoplastic usually are,these materials being commonly used to make spectacle frames, thebearing point is significantly shifted with respect to the rotation pinof the hinges, with the result that, for the same angle of over-opening,the return force of the sides must be much greater than in the case ofthin sides, to the extent that it impairs the wearer's comfort. The onlyoption for the optician to remedy this is to deform the sides of theframe, an operation that is all the trickier the thicker the sides.

The invention proposes a solution so that the return force of the springis the same from one frame model to another, and more precisely whateverthe thickness of the frame.

The type of spectacle frame to which the invention applies comprises aframe face on which two sides are articulated by telescopic hingesallowing the sides to move

-   -   from a stable open position, in which the hinge-side end, called        the “proximal end”, of the sides is parallel and in immediate        proximity to the hinge-side end, called the “proximal end”, of a        stub forming part of the frame face, the said proximal ends        defining a meeting plane passing between the knuckles of the        said hinge,    -   to an unstable over-opened position, by pivoting about a bearing        point lying in the said meeting plane, the sides having an        external surface and an internal surface, and the frame having a        plane of symmetry that is orthogonal to the general plane of the        frame face.

According to the invention, the said bearing point is located closer tothe said plane of symmetry than the external surface of the sides,measured at the level of the said meeting plane.

This position of the bearing point, which may be alternatively describedas “set back from the external surface of the side”, causes a frame withthick sides to behave like a frame with thin sides, with the result thatless force is needed on the hinge to obtain the same angle ofover-opening.

In one particular embodiment, the proximal end of the side and that ofthe stub have a meeting zone and the bearing point is located on theouter edge of the said meeting zone.

Advantageously, the proximal end of the side and/or that of the stub hasa recess, from the external surface of the said side and/or that of thesaid stub. This gives rise to a reduction in the thickness of themeeting zone compared to what it would be if the meeting zone were asthick as the side, and this reduction can be as much as to give thiszone the thickness of a metal side.

Preferably, the said recess, which may for example be a chamfer, reducesthe proximal end of the side and/or that of the stub to a thickness ofless than 1.5 mm; in other words, the meeting zone is less than 1.5 mmthick.

In another particular embodiment, the thickness of the meeting zone mayeven be zero or almost zero. Thus, the said recess may be in the form ofa gap of 1 mm to 5 mm between the proximal end of the side and that ofthe stub, in which case the bearing point is located on the hingeitself. This embodiment can be applied inexpensively to sides made ofacetate or injection-moulded thermoplastic. Specifically, all that isrequired is for this geometry to be provided for in the machining ofsuch sides, or in the shape of the injection mould, to obtain thedesired sides.

In the prior art, in the stable normal open configuration, the sides aresubstantially perpendicular to the frame face. For this purpose, thehinges are designed so that, in the normal open position, the externalsurfaces of the stub and the side are aligned when the proximal ends arein abutment. This means that in the position of over-opening by an angleα, generally of 2 to 8°, there is a not very attractive “break” in theline between the external surface of the stub secured to the frame faceand the external surface of the side.

To overcome this aesthetic disadvantage, the invention proposesintegrating the angle α in the design of the frame. To this end, in thestable normal open position, the external surface of the side makes anangle that is reentrant with respect to the plane of the externalsurface of the stub.

The invention will be more clearly understood on reading the followingdescription, in conjunction with the attached drawings, in which:

FIG. 1 a is a top view of the telescopic articulation zone of aspectacle frame with thin sides of the prior art, in the stable openposition;

FIG. 1 b is a top view of the same articulation zone as in FIG. 1 a butin the unstable over-opened position;

FIG. 2 a is a top view of the telescopic articulation zone of aspectacle frame with thick sides of the prior art, in the stable openposition;

FIG. 2 b is a top view of the same articulation zone as in FIG. 2 a butin the unstable over-opened position;

FIG. 3 a is a top view of the telescopic articulation zone of a framewith thick sides according to a first embodiment of the invention, inthe stable open position;

FIG. 3 b is a top view of the same articulation zone as in FIG. 3 a butin the unstable over-opened position;

FIG. 4 a is a top view of the telescopic articulation zone of a framewith thick sides according to a second embodiment of the invention, inthe stable open position;

FIG. 4 b is a top view of the same articulation zone as in FIG. 4 a butin the unstable over-opened position;

FIG. 5 a is a top view of the telescopic articulation zone of a framewith thick sides according to a third embodiment of the invention, inthe stable open position; and

FIG. 5 b is a top view of the same articulation zone as in FIG. 5 a butin the unstable over-opened position.

FIG. 1 shows part of one of the two thin sides 101 of a spectacle frameof the prior art, and part of the frame face 102 to which it isarticulated by means of a telescopic hinge C1, C2 whose pivoting point3, tie-rod 4 and return spring 5 are shown diagrammatically. The side101 comprises a hinge-side end 106, called the “proximal end”, which isparallel and in immediate proximity to a hinge-side end 113, called the“proximal end”, of a stub 107 forming part of the frame face 102. Theproximal ends 106 and 113 have a face-to-face zone or meeting zone Z1.The knuckles C1 and C2 likewise have proximal ends 15 and 16 facing eachother. The meeting zone Z1 lies in a meeting plane P, P′ passing betweenthe proximal faces 15 and 16 of the knuckles and the proximal ends 106and 113, respectively, of the side 101 and of the stub 107. The side 101has an internal surface 108 and an external surface 109. In FIG. 1 a,the side 101 is in the stable open position and its external surface 109is aligned with that 110 of the stub 107.

FIG. 1 b shows the same frame portion as FIG. 1 a but in this case ithas moved into the unstable over-opened position by pivoting about abearing point 111 located on the outer edge of the meeting zone Z1, inopposition to the force of the spring 5. In this position, the externalsurface 109 of the side 101 makes an angle α of between 2 and 8° withthe external surface 110 of the stub 107 of the frame face 102.

FIGS. 2 a and 2 b, in which elements that are the same as in FIGS. 1 aand 1 b bear the same references and elements that have been modifiedbut fulfil a similar role have the references shown in FIGS. 1 a and 1 bincreased by 100, differ from FIGS. 1 a and 1 b, respectively, only bythe fact that the face 202 and the side 201 are, in this case, thick.

Hence, as can be seen by comparing FIGS. 2 a and 2 b, the meeting zoneZ2 is thicker than the zone Z1 and, therefore, the distance between thebearing point 211 and the pivoting point 3 of the hinge is markedlygreater in the case of the thick side 201 than in the case of the thinside 101. As a result, for the same angle of over-opening, a greaterlength of tie-rod 4 must be pulled out of the hinge in the case of athick side 201, meaning that the spring 5 must be more compressed. Thespring therefore exerts a greater return force, which is uncomfortablefor the wearer.

FIGS. 3 a and 3 b, in which elements that are the same as in FIGS. 1 aand 1 b bear the same references and elements that have been modifiedbut fulfil a similar role have the references shown in FIGS. 1 a and 1 bincreased by 200, differ from FIGS. 2 a and 2 b, respectively, only bythe fact that the proximal end 313 of the stub 307 has a chamfer 12. Byvirtue of this chamfer 12, the meeting zone Z3 is reduced to a thicknessclose to that of the meeting zone Z1 and the bearing point 311 is closerto the pivoting point 3 than in FIG. 2 b, for the same side thickness.In fact, it may be at the same distance from the pivoting point 3 as inthe case of FIG. 1 b, which depicts a thin side 101.

FIGS. 4 a and 4 b, in which elements that are the same as in FIGS. 1 aand 1 b bear the same references and elements that have been modifiedbut fulfil a similar role have the references shown in FIGS. 1 a and 1 bincreased by 300, show one of the two sides 401 of a spectacle frameaccording to a second embodiment of the invention. This time, there is agap 14 between the proximal end 406 of the side 401 and the proximal end413 of the stub 407. The meeting zone Z4 now has a zero thickness andthe bearing point 411 coincides with the outer edge of the zone wherethe facing end faces 15 and 16 of the knuckles C1 and C2 of the hingemeet. By virtue of this gap 14, the bearing point 411 is as close aspossible to the pivoting point 3 since it is even closer than in thecase of the thin sides of FIGS. 1 a and 1 b, even though this is a framewith thick sides.

FIGS. 5 a and 5 b, in which elements that are the same as in FIGS. 1 aand 1 b bear the same references and elements that have been modifiedbut fulfil a similar role have the references shown in FIGS. 1 a and 1 bincreased by 400, show one of the two sides 501 of a spectacle frameaccording to a third embodiment of the invention. Unlike the precedingmodes of implementation, in the unstable over-opened position, theexternal surface 509 of the side 501 and the external surface 510 of thestub 507 are aligned in the unstable over-opened position, which is theposition in which the spectacles are worn. To achieve this look, changeshave been made to the proximal end 506 of the side 501 and to theproximal end 513 of the stub 507, and also to the facing end faces 515and 516 of the hinge C1′, C2′. More specifically, these ends 506, 513,515 and 516 are bevelled such that in the stable open position (FIG. 5a), the external surface 509 of the side 501 makes a angle α that isreentrant with respect to the plane of the external surface 510 of thestub 507. Except for this particular arrangement, the embodiment ofFIGS. 5 a, 5 b is of the same type as that of FIGS. 3 a, 3 b in that themeeting zone Z5 is thinner owing to the chamfering of the stub 507 at512. Thus, the bearing point 511 is closer to the pivoting point.

Naturally, the invention is not limited to the embodiments described andillustrated. Thus, for example, the chamfer 12 or 512 could be made inthe proximal end of the side instead of being made in the proximal endof the stub. Moreover, a recess made in any form other than a chamferwould also be possible.

1. A spectacle frame comprising a frame face on which two sides arearticulated by telescopic hinges allowing the sides to move from astable open position, in which the hinge-side end, called the “proximalend”, of the sides is parallel and in immediate proximity to thehinge-side end, called the “proximal end”, of a stub forming part of theframe face, the said proximal ends defining a meeting plane, passingbetween the knuckles of the said hinge, to an unstable over-openedposition, by pivoting about a bearing point lying in the said meetingplane, the sides having an external surface and an internal surface, andthe frame having a plane of symmetry, that is orthogonal to the generalplane of the frame face, wherein the said bearing point is locatedcloser to the said plane of symmetry, than the external surface of thesides, measured at the level of the said meeting plane.
 2. A frameaccording to claim 1, wherein the proximal end of the side and that ofthe stub have a meeting zone and in that the said bearing point islocated on the outer edge of the said meeting zone.
 3. A frame accordingto claim 1, wherein the proximal end of the side and that of the stubhave a meeting zone and in that the said bearing point is located on theouter edge of the said meeting zone, the thickness of the meeting zonegoing from a thickness smaller than that of the side to a zerothickness.
 4. A frame according to claim 1, wherein the proximal end ofthe side and/or that of the stub has a recess, from the external surfaceof the said side and/or that of the said stub.
 5. A frame according toclaim 1, wherein the proximal end of the side and/or that of the stubhas a recess, from the external surface of the said side and/or that ofthe said stub, said recess reducing the proximal end of the side and/orthat of the stub to a thickness of less than 1.5 mm.
 6. A frameaccording to claim 1, wherein the proximal end of the side and/or thatof the stub has a chamfer, from the external surface of the said sideand/or that of the said stub.
 7. A frame according to claim 4, whereinthe said recess is in the form of a gap of 1 mm to 5 mm between theproximal end of the side and that of the stub.
 8. A frame according toclaim 1, wherein, in the stable normal open position, the externalsurface of the side makes an angle (α) that is reentrant with respect tothe plane of the external surface of the stub.